Plasma physics and radiation hydrodynamics in developing an extreme ultraviolet light source for lithography
Plasma physics and radiation hydrodynamics in developing an extreme ultraviolet light source for lithography
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DOI：
10.1063/1.2907154
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发表时间：
2008-05-01
影响因子：
2.2
通讯作者：
Mima, Kunoki
中科院分区：
文献类型：
--
作者：
Nishihara, Katsunobu;Sunahara, Atsushi;Mima, Kunoki
激光产生的等离子体 (LPP) 产生的极紫外 (EUV) 辐射已被彻底研究用于下一代半导体器件的大规模生产。实现用于光刻的 LPP-EUV 光源的一个关键问题是从入射激光功率到 13.5 nm 波长（2% 带宽内）的 EUV 辐射的转换效率 (CE)。另一个问题是解决当碎片到达EUV收集镜时造成损坏的问题。在这里，我们提出了一种改进的功率平衡模型，可用于优化激光和目标条件以获得高CE。已经为目标设计开发了集成的数值模拟代码。该代码不仅与 CE 的实验结果非常吻合，而且与详细的 EUV 光谱结构的实验结果也非常吻合。我们提出了一种双脉冲照射方案，使用二氧化碳激光器和液滴或冲孔靶来实现高 CE 和减少离子碎片。使用我们的基准数值模拟代码，我们发现获得高达 6-7% 的 CE 的可能性，这是迄今为止所实现的两倍多。我们讨论了两脉冲辐照方案中离子能量的减少。还讨论了磁场对高能离子的缓解，我们得出的结论是，大离子回转半径不会发生严重的不稳定。 (c) 2008 年美国物理研究所。
Extreme ultraviolet (EUV) radiation from laser-produced plasma (LPP) has been thoroughly studied for application in mass production of next-generation semiconductor devices. One critical issue for the realization of an LPP-EUV light source for lithography is the conversion efficiency (CE) from incident laser power to EUV radiation of 13.5-nm wavelength (within 2% bandwidth). Another issue is solving the problem of damage caused when debris reaches an EUV collecting mirror. Here, we present an improved power balance model, which can be used for the optimization of laser and target conditions to obtain high CE. An integrated numerical simulation code has been developed for the target design. The code agrees well with experimental results not only for CE but also for detailed EUV spectral structure. We propose a two-pulse irradiation scheme for high CE, and reduced ion debris using a carbon dioxide laser and a droplet or a punch-out target. Using our benchmarked numerical simulation code, we find a possibility to obtain CE up to 6-7%, which is more than twice that achieved to date. We discuss the reduction of ion energy within the two-pulse irradiation scheme. The mitigation of energetic ions by a magnetic field is also discussed, and we conclude that no serious instability occurs due to large ion gyroradius. (c) 2008 American Institute of Physics.